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From: Helge Deller <deller@gmx.de>
To: qemu-devel@nongnu.org
Cc: Richard Henderson <richard.henderson@linaro.org>,
	Laurent Vivier <laurent@vivier.eu>,
	Paolo Bonzini <pbonzini@redhat.com>,
	Joel Stanley <joel@jms.id.au>,
	Akihiko Odaki <akihiko.odaki@daynix.com>,
	Helge Deller <deller@gmx.de>
Subject: [PATCH v6 4/8] linux-user: Do nothing if too small brk is specified
Date: Wed,  2 Aug 2023 01:27:41 +0200	[thread overview]
Message-ID: <20230801232745.4125-5-deller@gmx.de> (raw)
In-Reply-To: <20230801232745.4125-1-deller@gmx.de>

From: Akihiko Odaki <akihiko.odaki@daynix.com>

Linux 6.4.7 does nothing when a value smaller than the initial brk is
specified.

Fixes: 86f04735ac ("linux-user: Fix brk() to release pages")
Signed-off-by: Akihiko Odaki <akihiko.odaki@daynix.com>
Reviewed-by: Helge Deller <deller@gmx.de>
Signed-off-by: Helge Deller <deller@gmx.de>
---
 linux-user/syscall.c | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/linux-user/syscall.c b/linux-user/syscall.c
index ac429a185a..ebdc8c144c 100644
--- a/linux-user/syscall.c
+++ b/linux-user/syscall.c
@@ -820,14 +820,14 @@ abi_long do_brk(abi_ulong brk_val)

     /* brk pointers are always untagged */

-    /* return old brk value if brk_val unchanged or zero */
-    if (!brk_val || brk_val == target_brk) {
+    /* return old brk value if brk_val unchanged */
+    if (brk_val == target_brk) {
         return target_brk;
     }

     /* do not allow to shrink below initial brk value */
     if (brk_val < initial_target_brk) {
-        brk_val = initial_target_brk;
+        return target_brk;
     }

     new_brk = TARGET_PAGE_ALIGN(brk_val);
--
2.41.0



  parent reply	other threads:[~2023-08-01 23:28 UTC|newest]

Thread overview: 26+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2023-08-01 23:27 [PATCH v6 0/8] linux-user: brk fixes Helge Deller
2023-08-01 23:27 ` [PATCH v6 1/8] linux-user: Unset MAP_FIXED_NOREPLACE for host Helge Deller
2023-08-01 23:40   ` Richard Henderson
2023-08-01 23:27 ` [PATCH v6 2/8] linux-user: Do not call get_errno() in do_brk() Helge Deller
2023-08-01 23:27 ` [PATCH v6 3/8] linux-user: Use MAP_FIXED_NOREPLACE for do_brk() Helge Deller
2023-08-01 23:27 ` Helge Deller [this message]
2023-08-01 23:27 ` [PATCH v6 5/8] linux-user: Do not align brk with host page size Helge Deller
2023-08-01 23:27 ` [PATCH v6 6/8] linux-user: Show heap address in /proc/pid/maps Helge Deller
2023-08-02  5:41   ` Philippe Mathieu-Daudé
2023-08-02  6:07     ` Helge Deller
2023-08-01 23:27 ` [PATCH v6 7/8] linux-user: Optimize memory layout for static and dynamic executables Helge Deller
2023-08-02 18:25   ` Richard Henderson
2023-08-02 19:51     ` Helge Deller
2023-08-02 19:57       ` Richard Henderson
2023-08-02 20:06         ` Helge Deller
2023-08-01 23:27 ` [PATCH v6 8/8] linux-user: Load pie executables at upper memory Helge Deller
2023-08-02  7:49   ` Akihiko Odaki
2023-08-02  8:42     ` Helge Deller
2023-08-02  8:44       ` Akihiko Odaki
2023-08-02  9:34         ` Helge Deller
2023-08-02  9:58           ` Akihiko Odaki
2023-08-02 10:35             ` Helge Deller
2023-08-02 18:36   ` Richard Henderson
2023-08-02 19:57     ` Helge Deller
2023-08-02  2:21 ` [PATCH v6 0/8] linux-user: brk fixes Joel Stanley
2023-08-02  6:10   ` Helge Deller

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